[sergej-koscejev]

Closes #48

Summary

get node gains bounded views and readable output. The full Node Subtree stays the default.

 mops get node [--ancestry] NODE_REF
+  --depth N     N levels exported in full, level N as Node Stubs, top-level truncatedAt: N
+  --summary     find-style summary + children: {role: count}, no subtree
+  --compact     single-line JSON (pretty-printed by default)
+  stderr hint when an unbounded export exceeds 16 KB compact

Export shape with --depth 1:

{ model, concept, id, truncatedAt: 1, parent, properties, references,
  children: [ { role, concept, name?, reference, childCount }, ... ] }

Daemon side: ModelGetNodeRequest.depth flows into JsonNodeExporter, which recurses with a remaining depth (0 drops
children, 1 emits stubs); --summary is its own request pair (model-get-node-summary) built on the nodeSummary
that find and check already use. Both node commands get a customSynopsis so --help shows one line per positional
form.

Evidence

• Before: get node printed one ~43 KB line; get node --help showed NODE_REFERENCE | MODEL_TARGET NODE_ID [NODE_REFERENCE | MODEL_TARGET NODE_ID].
  After: GetNodeSemanticsTest (stubs at depth 1 and 2, truncatedAt, depth 0, summary counts and ancestry),
  ModelGetNodeCommandTest (pretty default, --compact byte-identical to the old output, option validation, stderr
  hint present/absent), DaemonProtocolJsonTest (round-trips, compact encoding unchanged), CommandHelpTest (synopsis).
  :protocol:test :daemon:test :cli:test green; integrationTestMps2026.1.1 for CliSmokeTest and
  BundledExamplesIntegrationTest green; :cli:updateExamples leaves the tree clean.

Decisions

• Stubs are MpsNodeJson instances with only role, concept, conceptValid, name, reference, and childCount set; no separate stub type, so the children list stays homogeneous and data-class equality keeps working in tests.
• Stubs carry reference (not the spec's ref), matching parent.reference, find output, and list --json, which all spell the serialized node reference as reference.
• Stubs also carry role, like every other child entry, so a consumer knows which containment role the stub sits in.
• --depth N means N levels below the target are exported in full and the nodes at level N are stubs; --depth 0 exports the target with no children key at all and truncatedAt: 0.
• truncatedAt is placed before parent in field order so head shows it; default output is unaffected because the field is omitted when null.
• --summary reuses the find/check summary vocabulary (MpsNodeSummaryJson: type, name, concept, reference, parent) and adds children: {role: count}; it is a separate request/response pair (model-get-node-summary) rather than an MpsNodeJson whose children changes shape. It is therefore not literally --depth 0 sugar: it lacks model, id, properties, references, and truncatedAt.
• Summary child counts are keyed in first-appearance order of the roles among the node's children.
• --summary and --depth are mutually exclusive (same rule as list); --ancestry combines with both.
• Pretty output uses two-space indentation.
• The size hint fires when the compact UTF-8 encoding exceeds 16 * 1024 bytes and reads mops: this node is N KB of compact JSON; pass --depth N or --summary for a bounded view; the compact form is encoded for the measurement even when the pretty form is printed, because the threshold is defined on it.
• The size threshold is covered by a CLI unit test with a synthetic large node; in test-projects/base-language-sandbox the largest export (the Calculator class) is 8 KB compact, so no fixture reaches the threshold and there is no fixture-based threshold test (the spec's premise about that project does not hold).
• The get node/render node synopsis is fixed with picocli customSynopsis as mops get node [OPTIONS] NODE_REFERENCE / ... MODEL_TARGET NODE_ID (the full option list would wrap at 80 columns), plus hideParamSyntax so the positional row in the parameter list is readable; the help-layout rework in Show subcommands near the top of help output #52 is left alone.
• --depth is validated as non-negative with no upper bound, unlike list, since a large depth simply degrades to the full export.
• GLOSSARY.md gains Node Stub; skills/mops/SKILL.md recommends --summary/--depth first on nodes that may be large.

Merge Danger

Door: two-way

Revert restores the previous single-line output; no persisted data changes.

Blast Radius: output-format

get node stdout is now multi-line by default. Scripts that parsed it as one line need --compact, which is
byte-identical to the previous output. MpsNodeSummaryJson gains an optional children field that find and check
never populate, so their output is unchanged.